Method and apparatus for generating ions and controlling electrostatic potentials

ABSTRACT

Method and apparatus for producing ions in a highly efficient manner and with a minimum of ozone for utilization in electrostatic control units and the like. A generator produces character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes. The energy generated is dispersed into a surrounding gas by being applied to one or more ionizing points spaced a preselected distance from one another and from a ground plate to generate ions. In those forms of energy dispersing apparatus having the gas moved at a preselected velocity the amount of ionization is substantially increased by reducing turbulence between the ionizing point and ground plate.

United States Patent 11 1 Bolasny 1 Jan. 16, 1973 [54] METHOD ANDAPPARATUS FOR 3,417,302 12/1968 Lueder ..3l7/262 AE GENERATING IONS AND3,624,448 ll/l97l Suurenmun et ul ..3l7/262 AE CONTROLLING ELECTROSTATICPrimary Examiner-L. T. Hix Attorney--Reilly and Lewis [57] ABSTRACTMethod and apparatus for producing ions in a highly efficient manner andwith a minimum of ozone for utilization in electrostatic control unitsand the like. A generator produces character-controlled periodicoscillatory pulses of electric energy having positive and negativecomponents of different amplitudes. The energy generated is dispersedinto a surrounding gas by being applied to one or more ionizing pointsspaced a preselected distance from one another and from a ground plateto generate ions. In those forms of energy dispersing apparatus havingthe gas moved at a preselected velocity the amount of ionization issubstantially increased by reducing turbulence between the ionizingpoint and ground plate.

33 Claims, 23 Drawing Figures POTENTIALS [75] Inventor: Robert E.Bolasny, Boulder, Colo.

[73] Assignee: Research Corporation, New York,

[22] Filed: April 14, 1971 [21] Appl.No.: 133,943

[52] US. Cl. ..3I7/3, 3 l7l4, 317/262 AE [51] Int. Cl. ..II0lt 19/00,HOlt 19/04 [58] Field of Search ..3l7/3, 4, 262 AB [56] References CitedUNITED STATES PATENTS 2,264,495 l2/l94l Wilner ..3l7/4 3,39l,3l4 7/l968Carter ..3l7/262 A 3,678,337 7/l972 Grauvogel ..3l7/262 AE 3,308,3443/1967 Smith et al. ..3 l7/4 r52 54 56 HP-LTJ 53 3! T ss PATENTED-JM 16I975 i SHEET 1 0F 6 INVENTOR ROBERT BOLASNY BY Q j lu Ok u ATTORNEYSPATENTEU JAN 16 I975 SHEEI 2 BF 6 PAIENIEDJAH 16 1975 3,711,743

SHEET 5 OF 6 PATENTEDJAH 16 1975 SHEET 8 [IF 6 IONS AND CONTROLLINGELECTROSTATIC POTENTIALS BACKGROUND OF THE INVENTION l.Field Thisinvention in general relates to the generation of ions in a body of gasand more particularly to a method and apparatus for producing ions whichis particularly effective in neutralizing undesirable electrostaticpotentials and the like.

2. Description of the Prior Art Industries such as aerospace,electronics, graphic arts, plastics and paper frequently require thecontrol of electrostatic potentials to maintain cleanliness, preventphysical damage to components, or difficulty in handling and toalleviate the danger of fire or explosion. Heretofore, the apparatus andmethods for generating ions useful in the field of electrostatic controlhave principally relied on the application of conventional SO-cycle and60-cycle sinusoidal electric line power to an ionizing point or points.The principal disadvantages of SO-cycle and 60-cycle sinusoidal electricpower is that the negative voltage levels have previously been in excessof K volts to effect satisfactory generation of ions. Negative voltagesin excess of 5K volts tend to produce ozone. Ozone has been found to behazardous to health and may degrade plastics, rubber, photographicfilms, drugs, etc. The 50-cycle and 60-cycle electric energy necessaryto generate the required voltage requires relatively large, bulky andexpensive power supplies. Past efforts to solve these problems in theproduction of ions have not proved entirely satisfactory and none arebelieved to offer the advantages of the present invention.

In prior attempts to increase the frequency of the ionizing energy,resort has been made to the use of a mechanical vibrator-type oscillatorand a center tap on a transformer to displace the phase of the 60-cyclepower to provide l-cycle sinusoidal power, but no prior art appears torecognize the advantages of controlling the character of the electricenergy, such as the amplitude, duration and frequency, for producingions, nor does the prior art recognize that ionization in a stream ofgas being moved under pressure may be increased by reducing theturbulence of the gas flow.

Some of the ionizing equipment presently available utilizes a pluralityof ring-shaped ground plates each having an ionizing point centeredtherein and to. which about 5,000 to 15,000 volts AC of 50 or 60-cyclesinusoidal electric energy is applied. This equipment has the effect ofthrowing ions out in a spotlight-type pattern and has a severely limitedcapacity since there is only about inch to 1% inch spacing between theionizing point and the circular ground plate. This type of equipmentdoes not lend itself to a widening or separation of the ion dispersingor distributing structure to the extent possible in the practices of thepresent invention.

Accordingly, it is a general object of this invention to provide ahighly efficient method and apparatus for generating ions.

Another object of this invention is to provide ionizing apparatus whichis as efficient at voltages below a negative 5K volts as the prior artis able to do substantially above a negative 5K volts and withsubstantially smaller power supplies.

Yet another object of this invention is to reduce the bulk of the unit,eliminate shock hazard and to reduce the possibility of production ofozone.

A further object of this invention is to provide for increasedionization by means of a reduction in the turbulence in the ionized gasflow.

SUMMARY OF THE INVENTION In accordance with the present invention in thepreferred embodiments herein there is provided a relatively compactelectric generator for producing periodic oscillatory pulses of electricenergy having positive and negative repetitive, character-controlledcomponents of different amplitudes at substantially lower negativevoltages together with a variety of energy dispersing structures coupledto the output of the generator for producing ions in a body of gas in ahighly efficient, relatively safe manner and with a minimum of ozone. Avelocity is imparted to the gas in some applications and in thoseapplications ionization is increased by reducing turbulence in the gasflow. The energy dispersing structure for electrostatic control takesthe form of an improved ion gun, improved portable units, improvedmodular units and an improved static bar to which the generator ispreferably affixed as an integral part.

DESCRIPTION OF THE DRAWINGS Other objects, advantages and capabilitiesof the present invention will become more apparent as the descriptionproceeds taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic circuit diagram of a generator for use inproducing ions in accordance with the present invention;

FIG. 2 is an illustration of the output waveform produced by thegenerator of FIG. 1;

FIG. 3 is an alternative form of conversion circuit for the generatorshown in FIG. 1;

FIG. 4 is a side elevation view of an ion gun embodying features of thepresent invention;

FIG. 5 is an enlarged fragmentary side elevation view of the nozzlesection of the ion gun shown in FIG. 4;

FIG. 6 is a perspective exploded view of a portable unit;

FIG. 7 is a vertical sectional view taken along lines 7-7 through thecenter of the ionizing cell portion of FIG. 6;

FIG. 8 is a modified form of portable unit with an external blower;

FIG. 9 is yet another form of portable unit which connects into a flowduct;

FIG. 10 is a perspective view of a modular unit with portions of the endcasing broken away to show interior parts and only a portion of thescreen and filter shown for clarity;

FIG. 11 is a sectional view taken along lines 1l--ll of FIG. 10;

FIG. 12 is an enlarged fragmentary perspective view showing thereleasable attachment of the grounding plates and support rods to theupright end casing;

FIG. 13 is an enlarged perspective view of a fastener for joining theends of ground plates and support rods;

FIG. 14 is a horizontal sectional view taken through the fastener ofFIG. 13;

FIG. is an enlarged perspective view of a fastener in a reversedposition from that shown in FIG. 14 using a screw to secure it to thescreen;

FIG. 16 is a perspective view of a releasable end coupling between upperand lower sections of the modular units;

FIG. 17 is a perspective view of an alternative form of ionizing cellfor the modular unit shown in FIGS. 10-16; I

FIG. 18 is a schematic diagram of a modular unit shown in FIGS. 10-16 inthe end of the duct-like body which may be a room;

FIG. 19 is a schematic diagram of a modular unit shown in FIGS. 10-16 ina laminar air flow workbench;

FIG. is a perspective view of a static bar unit viewing the undersidethereof;

FIG. 21 is a perspective view of a static bar unit shown in FIG. 20 inan inverted position;

FIG. 22 is an end elevation view of the static bar unit of FIGS. 20 and21 positioned over a moving web; and

FIG. 23 is an end elevation view of a modified form of static bar unitwith a pressurized gas flow input.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1 there isshown a generator circuit to which is applied commercial AC power,usually 105-129 or 220-240 volts at 50 or 60 cycles, represented as asignal generator 11 connected to input terminals 12 and 13. A groundterminal 14 is also shown at the input side. A power switch 15, shown inits open position, when closed connects the power from the signalgenerator to the generator circuit described hereinafter. i

A full wave rectifier-type circuit is provided for converting the ACline voltage to a desired level of DC voltage. This converter circuitincludes a bridge with two legs in parallel. One leg has a pair of zenerdiodes 16 and 17 connected back to back and the other leg has a pair ofrectifiers 18 and 19 connected back to back. The DC output terminalsdesignated 21 and 22 for the rectifier circuit are at a commonconnecting point for rectifiers 18 and 19 and a common connecting pointfor the zener diodes 16 and 17, respectively. A capacitor 23 isconnected in the line ahead of the rectifier circuit which serves as animpedance to initially reduce the line voltage. A capacitor 24 isconnected across the DC output terminals 21 and 22 of the full waverectifier circuit to reduce ripple in the DC. In sequence one half cyclewill cause one rectifier and one zener diode to conduct while the othersblock and on the other half cycle the other rectifier and zener diodeconduct while the first ones block. Each zener diode absorbs the excesscurrent not used by the oscillator circuit hereinafter described. Aresistor 25 is connected across capacitor 23 to prevent shock when thecircuit is disconnected from the power source signal generator 11 bymeans ofswitch 15.

The DC voltage at output terminals 21 and 22 is supplied to a blockingoscillator circuit. The blocking oscillator circuit includes an NPNtransistor 28 and a resistor 29 and inductor 31 connected between thebase electrode and DC terminal 21 and a resistor 32 connected betweenthe emitter electrode and DC terminal 22. The primary winding 33 of apulse transformer 34 is connected between the collector electrode to DCterminal 21. A series connected rectifier 35 and resistor 36 areconnected across the primary winding 33. Further, a series connectedcapacitor 37 and feedback winding 38 of the transformer connect betweenthe emitter electrode and at a common connecting point between inductor31 and resistor 29.

Reference is now made to the waveforms of FIG. 2 to explain theoperation of the above described electronic oscillator circuit which isessentially a blocking-type oscillator. The waveforms of current,voltage and instantaneous power or energy generated by the circuit areessentially the same and are each represented by waveform C shown inFIG. 2. A comparison of the voltage and current waveforms showed thatthe positive component of the current had a sharper initial increasethan the voltage but essentially the same decreasing slope and thenegative component of the current had a sharper initial decrease thanthe voltage, essentially the same decreasing slope and then dropped tozero more rapidly beyond the corona component. The corona componentsdescribed hereinafter appeared on the current waveform. In the operationof the oscillator over one cycle, resistor 29 charges capacitor 37 andprovides a bias current for the base electrode turning the transistorON. This connects the DC voltage across the primary winding 33 of thetransformer. This voltage in winding 33 is induced into feedback winding38 causing current to flow in capacitor 37, through inductor 31 and intothe base electrode of the transistor. This is a regenerative actionwhich also serves to turn the transistor ON and forms the rise for thepositive component designated a of the waveform. Component a may also bereferred to as the positive driven pulse.

The duration or time interval of the positive component is designated 1and is basically controlled by the resistance of the DC voltage supply,the inductance, resistance, and capacitance of the pulse transformer 34,the ON resistance and current gain of the transistor 28, the value ofcapacitor 37 and inductance of the inductor 31. The main function of theinductor 31 is to control the rate at which the capacitor 37 chargesfrom the regeneration current.

At the time when the regeneration current can no longer be sufficientlyamplified by the transistor 28 to maintain the increasing .primarycurrent required by the pulse transformer, the pulse transformerreverses its polarity and forms the negative component designated b asits magnetic field collapses in an attempt to maintain its current flow.At this time the transistor is biased to the OFF condition by the chargeon the capacitor 37 and the voltage of the negative component appearingacross the feedback winding 38. Rectifier 35 and resistor 36 provide apath for current flow during the interval of the negative componentdesignated m. The resistor 36 serves to control the amplitude of thenegative component. The duration and shape of the negative component bis controlled by the inductance and stray capacitance of the pulsetransformer 34. Component b may also be referred to as the.

negative flyback pulse. The time for the negative cycle of the waveformis controlled by the time it takes resistor 29 to discharge the biasvoltage on capacitor 37 and reverse its charge to the voltage wheretransistor 28 is again turned ON- by bias current flowing into the baseelectrode. Resistor 32 serves as a part of the source resistance for theDC supply voltage and as a device to protect the transistor 28 fromdamage due to excess current. Electric energy in the waveform producedin the primary winding 33 is stepped up in magnitude in the secondarywinding 41 of the pulse transformer and appears at output terminals 43and 44, output terminal 44 being connected to ground terminal 14. Acoupling capacitor 42 is connected in the line ahead of output terminal43 to limit the energy being coupled to the dispersing structuredescribed hereinafter.

Accordingly by selecting the circuit values above described theamplitude, duration and frequency of the positive and negativecomponents of energy may be directly controlled to effect maximumionization. The energy thus generated by the circuit may becharacterized as being repetitive, character-controlled positive andnegative components. The waveform shown in FIG. 2 representing electricenergy provided by the circuit may further be characterized as periodicin that it repeats itself regularly in time and form, oscillatory inthat it goes both positive and negative with respect to a zero potentialand pulses because it has momentary sharp changes. The ratio of theduration of the positive component and the negative component isbalanced against the ratio of the amplitude of the positive component ofenergy and the amplitude of the negative component of energy to effectan optimum balance of positive and negative ionization while controllingpositive and negative corona and ozone generation. The amplitude of thepositive component is also controlled directly by the turns ratio of thepulse transformer 34.

In the above described circuit the component values are selected so thatthe waveform repeats preferably at a frequency in excess of linefrequency and usually in excess of twice the line frequency, and may beas high as KHz, which may be considered in the high audio frequencyrange.

Test results using the above circuit show that a positive corona appearson the current waveform at a value corresponding with a positive peakoutput voltage of about 5 ,000 volts DC and that for best results inpositive peak output voltages are between 7,000 volts DC and 8,600 voltsDC for component a. The peak current value at 8,600 volts is about 600microamps. In this range of positive voltages the positive corona may beobserved on the current waveform by a component represented in FIG. 2 atd. This positive corona component is diffuse, faint and highly irregularin amplitude and intensity. The amplitude of this positive coronacomponent is comparable to positive component a which is more in theform of a pulse or envelope. In the test results a negative corona wasfound to appear on the current waveform at a value corresponding withabout 3,000 volts DC for component b. The waveform corona component isrepresented as riding on the waveform component b and is designated e.The negative corona component e was observed as being of a somewhatsaw-toothed shape, orderly and of constant amplitude. The negativecorona component e follows the declining crest of the negative componentb and appears for a shorter time interval than interval m which isdesignated n. It was found that the negative corona component e began toappear at 3,000 volts DC and the number of the spikes per cycleincreases as the negative volts increased to 4,300 volts DC. The peakvalue of the current waveform at 4,300 volts DC is about 300 microamps.At 4,300 volts DC as shown in FIG. 2 the maximum number of spikesoccurred in negative corona component e and the maximum negativeionization of the gas occurred. Above 4,300 volts ozone was found tooccur.

Both positive and negative, relatively high DC voltages, on the order of5,000 volts, are derived from the output across the secondary winding 41of the above described circuit which may be used with an electrostaticfilter or applied to a static generator. The propagation of a relativelyhigh positive or negative voltage on the order of 5 ,000 volts isbelieved to benefit general health or mental attitude. To this end thesecondary winding 41 is provided with a tap line 45 so that the electricenergy or power from the secondary winding is connected into a positivecascade voltage doubler circuit comprised of capacitor 46 connectedahead of a delta network of high voltage rectifiers 47 and 48 andcapacitor 49, the output terminal for the positive cascade voltagedoubler circuit being designated 51. The tap line 45 also connects to anegative cascade voltage doubler circuit comprised of a capacitor 52connected ahead of a delta network of high voltage rectifiers 53 and 54and capacitor 55, the output terminal for the negative voltage doublercircuit being designated 56.

In a full sequence of operation for the generator circuit, the AC inputpower from the line is converted to DC power which is then applied tothe blocking oscillator circuit. In the blocking oscillator circuitthere is formed a waveform C having repetitive, character-controlledpositive and negative components of energy a and b, respectively, whichpreferably differ from each other both in amplitude and durationtogether with the superposed corona components d and e for maximumionization of a body of gas. This energy is applied to active electrodesterminating in one or more ionizing points spaced from ground plates forsimultaneously producing both positive and negative ions in thesurrounding body of gas as described fully hereinafter.

An alternative converter circuit to that shown in FIG. I is illustratedin FIG. 3. Whereas the converter circuit of FIG. I is specificallyadapted to mount on the same circuit board as the other circuitcomponents, the AC to DC converter arrangement of FIG. 3 may be builtinto a wall box type plug. Commercial 220-240 volt AC power at 50 or 60cycles is represented by a signal generator 58 and connects across inputterminals designated 59 and 61. Commercial -129 volt AC power at 50 or60 cycles is represented by a signal generator 62 connected across inputterminals 63 and 61. A power switch 64, shown in the open position, whenclosed connects the AC power to the converter circuit describedhereinafter.

The converter circuit comprises a step-down transformer 65 having aprimary winding 66 connected across input terminals 59 and 61 and acenter tap of the primary winding is connected to input terminal 63. Thevoltage from the signal generators is stepped down in the secondarywinding 67 and applied across a full wave rectifier bridge designated 68comprised of four suitably connected rectifiers and the rectified DCthen appears at terminals 21 and 22 with a smoothing ION GUN One form ofhigh velocity, low volume, energy dispersing structure to which theabove circuit is connected is an ion gun shown in FIGS. 4 and 5. Thision gun, in general, comprises a barrel or tubular body 71 in whichthere is mounted adjacent its discharge end an electrode pin 72terminating in an ionizing point surrounded by a washer-like or annularground plate 73. The barrel terminates in removable nozzle or head 74having a central discharge orifice 75 and side intake venturis 76 whichconverge from inlet to outlet ends thereof. The head 74 is shown asbeing provided with external threads which thread .into internal threadsformed in the end of the barrel. The ground ring 73 is placed in the endof the barrel and the head is threaded thereinto so that the head holdsthe ground plate in place in the discharge end of the barrel.

The electric line power is coupled to the generator circuit in a housing77 via line 78 and from which there extends an active line 79 releasablyconnected to the electrode by a connector sleeve 80 and a ground line 81connected to the ground ring 73. The electrode pin is centered andreleasably supported in the barrel on a cradle-like support 88. Thehousing 77 and barrel are shown as being made integral with one anotherand a bracket 84 connects one end of the housing to a handle section 82.

A gas, usually air, under pressure is introduced into the inlet end ofthe barrel via a passage in the handle section 82 which contains an airflow control valve actuated by a trigger 83. A male fitting 85 withexternal threads is shown as releasably coupling the handle section intothe barrel and a male fitting 86 with external threads is shown asreleasably coupling a pressure line 87 into the handle section via ahole in bracket 84 so that the housing 77 is releasably supported on thehandle section 82. Upon actuation of the trigger 83 a gas under pressurewill be forced past the ionizing point and through the nozzle dischargeorifice 75 to produce ions which may be directed onto a variety ofsurfaces requiring electrostatic neutralization.

PORTABLE UNITS A portable unit shown in FIGS. 6 and 7 comprises anopen-ended elongated hollow casing 89 which converges or tapers inwardlyfrom its inlet end toward the outlet end. This convergence serves toattain the maximum air flow velocity from the internally mountedmotor-fan unit 105 described hereinafter. The casing 89 has a U-shapedflange 91 mounted on the bottom thereof and an internally threadedwasher 92 on the flange facilitates its support on a base 93 by asuitable fastener such as a headed bolt 94. The base may take variousforms such as a handle so that it may be handheld or a jointed armadapted to mount on a flat topped surface such as a bench top. Theionizing cell for this unit includes a single ionizing electrode pin 95mounted in the center of the discharge end of the'casing and the pin 95extends longitudinally thereof. A ground ring or annulus 96 formedpreferably of a metal foil is mounted along the inner peripheral edge ofan annular end cap 97. The end cap 97 supports a latticelike grid orduct assembly 98 which in turn provides support for the ionizingelectrode pin. This duct assembly 98 is made up of a plurality ofrelatively wide intersecting strips with one group of spaced parallelstrips 98a arranged parallel to one another and another group of strips98b parallel to one another and at right angles to the first group andin this way a center duct 980 is formed. The ionizing electrode pin isslidably mounted in a cup-shaped support 99 located in the center duct980. A light shield 101 has a base portion which fits over the centerduct and has an imperforate head portion normal to the gas flow. Anactive line 102 extends through the center of base 99 and connects toelectrode pin 95. A ground line 103 connects to the ground ring 96. Theduct assembly 98 serves to direct the gas flow between the ionizingelectrode pin and ground ring 96 with a minimum of turbulence, which hasbeen found to increase ionization.

A motor-fan unit 105 is mounted in a removable end frame 106 slidablyreceived in the intake end of the casing. A pair of corrugated filters107 and 108 turned at right angles to one another slidably fit into arecess in the intake end of the frame 106 to cover the fan unit andremove particulates from the ionizing gas. The generator circuitry ismounted in a relatively compact housing 109 which inserts into theU-shaped support flange 91 and is held in place by the end frame 106.Line power is connected into the housing via line 110.

In the operation of the portable unit shown in FIGS. 6 and 7 theionizing energy applied to pin 95 produces an electric field between thepoint of the pin and ground ring 96. The gas flow in the directionindicated by arrows causes the electric field produced to bow outwardlyin the direction of the gas flow as shown in dashed lines causingionization of the body of gas between the pin 95 and ring 96.

In FIG. 8 there is shown a portable unit which is similar to that shownin FIGS. 6 and 7 but has a tubular cylindrical casing 111 of uniformcross section throughout its length having a housing 112 mounted thereonfor the generator circuitry with a power con trol switch 112a on thehousing. A circular ionizing cell and duct assembly 113 are mounted atthe discharge end of the casing with a single ionizing pin 113a at thecenter of the cell surrounded by a lattice-like duct assembly. Aconventional centrifugal blower assembly 114 is mounted at the intakeend of the casing to illustrate an external fan arrangement for forcingair through the ionizing cell 113. In FIG. 9 there is shown the sametubular cylindrical casing 111 supporting a housing 112 having an on-offpower control switch 112a. The casing is mounted in a gas flow ductrepresented at 115 which typically could be placed in any air flow linedelivering air to a room in a building.

MODULAR UNITS A modular unit generally designated A, shown in FIGS.10-16, in general includes an upright end casing 1 16 providing supportfor one end of a matrix-type pattern of ionizing cells, each cell beinggenerally designated 1 17 and arranged in the same plane in verticallyspaced rows rising one above the other and in spaced aligned columnsadjacent a screen 119 and a filter 120. A gas, usually air, is movedtherethrough in the direction shown by the arrows in FIG. 11, firstthrough the filter 121), then the screen 119 and then past each cell.The screen 119 is of aluminum sheet material with multiple perforationsand the filter is a high efficiency particulate air-type filter commonlyknown in the trade as a l-IEPA filter. Only a portion of the screen andfilter are shown in FIG. 10 for clarity but it is understood that theyare coextensive with the rear face of all of the ionizing cells 1 17.

The end casing 116 is hollow and houses a generator circuitry such asthat above described in FIGS. 1-3. A printed circuit board 121 insidethe casing extends the full length thereof and supports the generatorcircuit. A conductive strip 122 in the board provides a common connectorfor the output of the generator to each active electrode. A conductivestrip 123 in the board 121 provides a connector for each ground plate.An on-off control switch 124 is mounted on the casing as well as a meter125 for measuring and indicating current flow of the generator. Inputelectric line power is connected to the generator through a cordrepresented at 126. The upper end of the casing 116 is provided with afemale electric socket 127 and the next above casing designated 116 hasmale prongs 128 on its lower end as best seen in FIG. 16 arranged toreleasably insert into the female socket 127 of the lower casing so asto provide for a vertical alignment of the two end casings and anelectrical connection between two stacked modular units. This electricconnection may be to transfer either the line power or electric ionizingenergy from the generator to the next above modular unit and alsoprovides a ground connection.

Each row of the ionizing cells 117 is formed by a set of verticallyspaced upper and lower interchangeable ground plates 131 and 132,respectively, with an interchangeable horizontal support rod or activeelectrode 133 preferably located midway between the ground plates andparallel thereto and having a plurality of ionizing electrode pins 134at spaced intervals along the support rod. Each ionizing pin terminatesat its distal end in a sharp ionizing point 135.

As best seen in FIG. 11, the ground plates and the support rod areshaped in cross-section as an airfoil section presenting upper and lowerconcave surfaces to the gas flow to provide minimum flow resistance andminimize turbulence. The electrode pins 134 are mounted on one edge ofthe airfoil section with the distal end pointing away from the incominggas flow. The sets of upper and lower ground plates for the modular unitshown are arranged in three tiers with three ionizing pins being in avertical alignment.

As an alternative the ionizing cells 117a may be shaped so that theupper ground plate has a series of alternating straight sections 131aand upwardly extending arcuate sections 131b and in turn the lowerground plate may be shaped with a series of alternating straightsections 132a and downwardly extending arcuate sections l32b with a pinmounted on the support rod 133 centrally located in the arcuatesections. Each upper arcuate section is in a vertical alignment with alower arcuate section and these sections are in a concentric arrangementabout the ionizing pin 134 so that the gas flows through a generallycircular ground plate structure.

The outer end of the upper and lower ground plates 131 and 132 andsupport rods 133 for each modular unit releasably inserts throughopenings in the end casing 116 and are held by a flexible fastener 138.Fastener 138 engages strip 123 to make an electric contact. The inneradjacent ends of the ground plates are arranged to be releasably coupledtogether so that a selected widthof assembly of modular units may bemade up as required. To this end, as best seen in FIGS. 13 and 14, theadjacent ends of two ground plates overlap with one end having a steppedportion 136 with a slot 136a and the other a raised portion 137extending into the slot 136a. A releasable fastener 138 in the form of aclip fits over the overlapping ends to secure them end to end and inalignment with one another. The clip fastener 138 has a lower loopportion 139 encompassing the overlapping ends of the adjacent groundplates, an upstanding vertical portion 141 with an aperture 142 and anupper downturned hook portion 143. The hook portion 143 is positioned tohook into the screen 119 to support the plate or rod therefrom or in thealternative the clip may be turned around and a screw 144 may extendthrough the aperture 142 and fasten into the screen 119, as best seen inFIG. 15. The active electrodes or support rods 133 releasably connecttogether in the same way with fasteners 138.

Two examples of typical commercial applications for the modular unitsare shown in FIGS. 18 and 19. In FIG. 18 a plurality of modular unitsdesignated A, B, C and D are stacked one on another to form a compositemodular assembly at one end of a hollow duct-like member generallydesignated 146. The duct-like member 146 is closed on all sides and maybe a duct in an air conditioning system, a room in a building and thelike. Member 146 includes a top wall 147, a bottom wall 148 and opposedside walls 149 and 151 and is shown as having a recirculation duct 152along the ends and top together with a blower 152 to provide means forcirculating a gas through the duct-like member 146.

In FIG. 19 a single modular unit A is mounted in an upright position atthe rear end of a clean room or laminar air flow-type workbench 154.This modular unit has essentially a duct-like member located forwardlyof the modular unit including an upper cover 155, lower work table 156and side walls 157 and 158 arranged together to confine and direct thegas flow through the ionizing cells of the modular unit A. A circulationduct 159 behind the modular unit directs air flow from a blower 161through the modular unit and out the duct-like member in which work isbeing carried out.

In the operation of the above-described modular units the gas flowthrough the electric field between the ionizing points and ground platesmoves ionized gas in the direction of gas flow. This ionization of thegas tends to dissipate in effectiveness as the space between theionizing point and ground plates increases. In both the above describedportable and modular units the control static energy is almost entirelyby the ionized gas particles giving up their energy to reduce theelectrostatic potential on an object. The relatively large open areaprovided between the ionizing point and ground plate provided by thedispersing structure of the present invention generates a relativelylarge and uniform electric field. Gas passing through this field isbroken apart creating charged molecules commonly called ions. It wasfound that if control grid or latticelike duct assembly is placed in thegas flow the amount of turbulencev has been considerably reducedpermitting the ions to be carried by the force of the gas a much longerdistance with a minimal recombination and results in increasedionization.

A comparison of the velocity and volume ranges of the above describedion gun, portable units and modular units helps to differentiate in thepossible application in which they are used. The ion gun may becharacterized as a high velocity, low volume unit. The portable unit ofFIGS. 6 and 7 may be characterized as a medium velocity and mediumvolume unit, and the portable units of FIGS. 8 and 9 may range frommedium to high velocity and medium to high volume. With regard to themodular units of FIGS. 10-16, in an air conditioning system it mayoperate at a high volume and high velocity whereas in a bench-type unitas shown in FIG. 19 it would be a medium volume and medium velocityunit. For a comparison of volumes and velocities the followingapproximate values are used:

High Velocity 4000 fpm and above Medium Velocity 1000 fpm Low Velocity500 fpm and below High Volume 2000 Cfm and above Medium Volume I Cfm LowVolume Cfm and below STATIC BARS Referring now to FIGS. 20 and 23, astatic bar-type device is shown which includes an outer elongated U-shaped or channel support member 163 normally inverted in the operableposition having a pair of spaced parallel sides 164 and 165 and anintermediate top section 166 connecting the sides. I-Ioles 166a areprovided in member. 163 for mounting the device above a moving webrepresented at 169. A pair of conductive strips 167 and 168 are mountedalong the lower extremities of theinner surfaces of the sides of thesupport member and extend. the full length thereof to form the groundplates for the energy dispersing structure. Side 165, which is theleading side relative to the moving web represented at 169, is providedwith a lateral extension or extended section 171 terminating in aserrated edge defining points 172 which forms an induction devicepositioned ahead of the active ionizing portion to initially reduce thestatic charge on the moving web 169.

An elongated active electrode rod 173 extends along the inside of thesupport member and has a plurality of spaced ionizing electrode pins 174at regularly spaced intervals along the rod, the rod 173 being shown asoffset to one side of the center of the support member 164 and the pins174 inclined downwardly toward the web and each terminating in anionizing point located at the center of the support member and passingbeyond slot 177 only a short distance.

A channel-shaped cover member 176 has a pair of spaced parallel sidesextending in opposite directions from that of the support member and arespaced to slidably fit into the open side of the support member.

Member 176 has elongated slots 177 centered in the 178 to direct airpast the ionizing pins and confine air under pressure therein if theunit is pressurized. A downwardly bowed .light shield 179 slidably fitsbetween the sides of the support member and extends across the open endthereof. The light shield has a series of inwardly bowed longitudinallyextending side edges 179a formed therein. The leading side of thesupport member is provided with elongated slots 181 which facilitate thecirculation of a gas flow from the moving web through the channel andout of the center slots 177 surrounding the ionizing pins. Thisadditional gas flow about the ionizing pins has been found to increasethe ionization and efficiency of the device.

The energy generator circuit is mounted in a housing 183 positioned onthe top and at one end of the support member 163. Power is connectedinto the generator by a cord represented at 184. This arrangement withthe energy generator integral with the support member makes an assemblywhich is much more compact and easier to operate.

A modified form of static bar is shown in FIG. 23 having the side slots181 closed and a gas under pressure shown schematically as beingproduced by a blower 186 is introduced through a flow line 187 into theside of the support member and causes the electric field between theionizing points to extend further from the apparatus and produceincreased ionization. For relatively short static bars a single inletflow line opening into the support member may be used but for relativelylong static bars the gas under pressure may be introduced at severalpoints along the bar such as by means of a manifold structure or thelike.

In the static bar units above described the induction device 171 isusually placed approximately one-fourth inch to one inch from the movingweb and serves to reduce the electrostatic energy on a moving web beforeit passes through the electric field produced by the ionizing cells orpowered portion of the static bar.

In the static bar units there is provided a relatively wide spacingbetween the ionizing points and the conductive strips forming groundplates on the channel and the objective here is to provide maximumquantity of ions per unit of time. In the form shown a satisfactoryspacing between the ionization point and ground plate is 0.75 inches.Three factors reduce static charges on the moving web 169. First, as theweb reaches the induction points, charge flows from the web to pointswhich are at a ground potential. This effect is helped by a weak ionfield carried forward from the induction points 171. The inductiondevice serves to reduce the charge to about 4 Kv to 5 Kv at optimumconditions. The distance from the induction points and the web ispreferably between one-quarter inch to one inch depending on the charge.The web passes under an intense field of ionization and the ions serveto make the gas more conductive, permitting the charge to move from theweb to the. grounded edges of the channel. A secondary effect inreducing charge is gained by the ions giving up their energy to reducethe charge. The third effect is due to air flow through the channel inthe direction of travel of the ion spread adding time for the ions toreduce charge. The ionization points of the bar preferably are spaced 1to 3 inches from the web. The relatively wider bar provides more timefor the web to be under its influence and therefore a more completeremoval of the charge on the web.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade by way of example and that changes in details of structure may bemade without departing from the spirit thereof.

What is claimed is:

1. In a method of producing ions with greater efficiency and a minimumof ozone, the steps of:

generating character-controlled periodic oscillatory pulses of electricenergy having positive and negative components of different amplitudes,and applying the generated electric energy to an ionizing pointsurrounded by a body of gas to generate ions.

2. In a method of producing ions as set forth in claim 1 furtherincluding the step of moving the gas at a preselected velocity.

3. In a method of producing ions as set forth in claim 2 furtherincluding the step of minimizing the turbulence of the flow of the gasto increase the ionization thereof.

4. In a method of producing ions with greater efficiency and a minimumof ozone comprising the steps of:

converting low. frequency electric line power to a,

character-controlled periodic oscillatory pulses of electric energyhaving positive and negative components of different amplitudes,

separately controlling the amplitude of each of said positive andnegative going components of electric energy to maximize the productionof positive and negative ions and minimize the production of ozone; and

applying the generated energy to an ionizing point surrounded by a bodyof gas so as to simultaneously produce positive and negative ions.

5. In apparatus for generating ions generator means for producingcharacter-controlled periodic oscillatory pulses of electric energyhaving positive and negative components of different amplitudes,

dispersing means for said energy including an ionizing point to whichthe generated energy is applied and a ground plate a preselecteddistance from the ionizing point for producing ions in a body of gasbetween said ionizing point and ground plate.

6. In apparatus as set forth in claim 5 wherein said generator means isoperable to generate a waveform having positive and negative repetitivecomponents of electric energy having a repetition rate for a full cyclein excess of twice the line power frequency.

7. In apparatus as set forth in claim 5 wherein the amplitude of eachpositive component of energy is substantially in excess of the amplitudeof each of said negative components of energy.

8. ln apparatus as set forth in claim 5 wherein said positive andnegative components of electric energy are pulses.

9. In apparatus as set forth in claim 5 wherein the peak value of eachsaid positive component of energy is in the range of 7,000 to 8,600volts.

10. In apparatus as set forth in claim 5 wherein the peak value of eachsaid negative component of energy is in the range of 3,500 to 4,300volts.

1 1. In apparatus as set forth in claim 5 further includ- 6 ing meansfor moving the gas between the ionizing point and ground plate at apreselected velocity.

12. In apparatus as set forth in claim 11 further including means forreducing the turbulence of the moving gas. 7

13. In apparatus as set forth in claim 5 wherein said generator meansincludes:

a converter circuit for changing an input low frequency line voltage toa DC voltage,

an electronic oscillator for changing said DC voltage to a waveformhaving repetitive, character-controlled positive and negative componentsof electric energy, said waveform having a frequency above Hz, and

a transformer for stepping up the voltage of the waveform produced bysaid electronic oscillator.

14. In apparatus as set forth in claim 13 wherein said electronicoscillator is a blocking type oscillator circuit which produces apositive driven pulse and a negative flyback-type pulse.

15. In apparatus as set forth in claim 13 further including AC to DCconverter means to convert components of electric energy to separatepositive and negative DC voltages.

16. In apparatus as set forth in claim 13 further including input meansfor applying a low frequency alternating current electric power to saidconverter circuit.

17. In apparatus for producing ions and controlling electrostaticpotentials,

energy dispersing structure including a ground plate and an ionizingelectrode terminating in an ionizing point electrically insulated fromthe ground plate and spaced a preselected distance from the groundplate, and

electric generator means secured to the dispersing structure forconverting input electric line power to character-controlled periodicoscillatory pulses of electric energy having positive and negativecomponents of different amplitudes coupled to said ionizing electrode toproduce ions in a body of gas between the ionizing point and said groundplate.

18. In apparatus as set forth in claim 17 wherein said energy dispersingstructure includes an upright end casing containing the electricgenerator means, conductive means extending through the casing, and asupport rod releasably connected at one end to the conductive meanssupporting a plurality of spaced electrode pins with the ends of thepins defining ionizing points, said ground plate being defined by spacedupper and lower conductive plates above and below said support rod,respectively.

19. In apparatus as set forth in claim 18 wherein said conductive meansis in the form of a first conductive strip on a printed circuit board towhich said support rod connects and a second conductive strip on saidboard to which said conductive plates connect.

20. In apparatus as set forth in claim 17 wherein said energy dispersingstructure includes an elongated hollow casing, said ground plate beingdefined by a conductive ring mounted in a removable head at thedischarge end of the casing and an electrode pin mounted at the centerof said conductive ring with a sharp point on the end of the pindefining said ionizing point, and further including a lattice-like gridassembly across the gas discharge end of the casing between said ringand pin formed of a plurality of flat intersecting non-conductive stripsfor directing a gas flow of relatively high velocity through theadjoining body of gas in a nonturbulent flow.

21. In apparatus as set forth in claim 17 wherein said energy dispersingstructure is a generally channelshaped member with conductive portionson the ends thereof forming the ground plates, said ionizing point beingdefined by an electrode pin mounted in the channel-shaped member betweensaid end portions, one side wall of said channel-shaped member havingelongated slots to direct a gas flow along the ionizing points.

22. In apparatus as set forth in claim 17 wherein said energy dispersingstructure is a barrel terminating in a high velocity nozzle head with aring inside the head forming the ground plate, said ionizing point beingdefined by an electrode pin mounted in the center of the barrel upstreamof the nozzle head, said head having venturi-like intake sectionsupstream of the ionizing point.

23. In apparatus for producing ions and controlling electrostaticpotentials in a duct-like body having a filter and screen across anintake end thereof and having means for circulating the gas through theduct-like body at a preselected velocity, v

a modular assembly mounted at the intake end of the duc t Iike bodyadjacent the filter and screen made up of a plurality of modular unitsreleasably connected and stacked one on another, each said modular unitincluding an upright end casing having an internal printed circuitboard,

a matrix-typepattern of ionizing cells supported at one end of thecasing and arranged in vertically spaced rows and in spaced alignedcolumns includmg a first group of generally horizontal support rodsarranged at vertically spaced intervals and arranged parallel to oneanother, each support rod having one end releasably secured to the endcasing at one end,

a second group of generally horizontal support rods releasably connectedend to end to another one in the first group, each said support rodhaving a plurality of electrode pins arranged at equally spacedintervals therealong having end points located in the same planedefining a plurality of ionizing points,

an upper ground plate positioned above each support rod and a lowergrounding plate below each support rod, and

a generator mounted in the end casing having an output terminalconnected to said ionizing points for converting electric line power tocharacter-controlled periodic oscillatory pulses of electric ionizingenergy having positive and negative components of different amplitudes,said end casing having releasable coupling means for electrically andmechanically connecting to each casing of each successive unit.

24. In apparatus for producing ions and controlling electrostaticpotentials in a body of gas, a hollow casing, an ionizing cell at thedischarge end including a conductive ring forming a ground plate and anelectrode mounted at the center of said ringhaving a terminal enddefining an ionizing point,

a lattice-like flow control duct assembly across the discharge end ofthe casing including a plurality of intersecting non-conductive stripsdefining a plurality of ducts in the one end of the casing for directinggas between the ionizing point and ground plate in a non-turbulent flow,

gas-flow generating means operatively associated with the casing fordirecting a relatively high velocity body of gas through the casing fromthe intake to the discharge end thereof, and

a generator mounted on the casing having an output terminal connected tosaid electrode for applying character-controlled periodic oscillatorypulses of electric ionizing energy having positive and negativecomponents of different amplitudes to said electrode for producing ionsin said body of gas. 25. In apparatus as set forth in claim 24 whereinsaid casing converges in cross section from the intake to the dischargeend.

26. In apparatus for controlling electrostatic potentials as set forthin claim 24 wherein said gas-flow generating means is an axial fanmounted at the gas intake end of the casing.

27. In apparatus as set forth in claim 24 wherein said gas-flowgenerating means is a centrifugal blower mounted on the gas intake endof the casing.

28. In apparatus as set forth in claim 24 wherein said casing is open ateach end and adapted to couple into a duct to utilize the gas flowpassed through that duct to move the gas.

29. In apparatus for producing ions and controlling electrostaticpotentials, the combination comprising:

a barrel having a gas inlet and terminating in a nozzle head having aninlet and a restricted outlet,

a ring-shaped ground plate mounted in the barrel and coaxially alignedtherein,

an electrode pin centered in the barrel terminating in an ionizing pointlocated in coaxial alignment with the ground plate,

means for introducing a gas under pressure into the inlet of the barrelto flow between said ground plate and electrode pin, and

generator means mounted on the barrel for producing periodic oscillatorypulses of electric ionizing energy having positive and negativecomponents of different amplitudes for producing ions in a body of gasbetween said ionizing point and ground plate.

30. In apparatus as set forth in claim 29 further including a handlesection containing a valve for controlling the gas flow into the barrel,said generator means being mounted in a housing integral with saidbarrel and releasably attached to said handle section.

31. In apparatus for producing ions and controlling electrostaticpotentials,

an elongated generally U-shaped support member having a plurality ofelongated slots in one side thereof to induce a gas flow thereinto, saidsupport member having an induction member forming an extension of oneside thereof,

a plurality of ionizing points in the support member 6 defined by anelongated support rod extending longitudinally of the support memberhaving electrode pins projecting therefrom at regularly spacedintervals, and

of said support member, said cover member having restricted openingsthrough which said electrode pins extend.

33. In apparatus as set forth in claim 32 further including means todirect a gas under pressure into the inside of said support member to bedirected through said restricted openings and past said electrode pins.

2. In a method of producing ions as set forth in claim 1 furtherincluding the step of moving the gas at a preselected velocity.
 3. In amethod of producing ions as set forth in claim 2 further including thestep of minimizing the turbulence of the flow of the gas to increase theionization thereof.
 4. In a method of producing ions with greaterefficiency and a minimum of ozone comprising the steps of: convertinglow frequency electric line power to a, character-controlled periodicoscillatory pulses of electric energy having positive and negativecomponents of different amplitudes, separately controlling the amplitudeof each of said positive and negative going components of electricenergy to maximize the production of positive and negative ions andminimize the production of ozone; and applying the generated energy toan ionizing point surrounded by a body of gas so as to simultaneouslyproduce positive and negative ions.
 5. In apparatus for generating ionsgenerator means for producing character-controlled periodic oscillatorypulses of electric energy having positive and negative components ofdifferent amplitudes, dispersing means for said energy including anionizing point to which the generated energy is applied and a groundplate a preselected distance from the ionizing point for producing ionsin a body of gas between said ionizing point and ground plate.
 6. Inapparatus as set forth in claim 5 wherein said generator means isoperable to generate a waveform having positive and negative repetitivecomponents of electric Energy having a repetition rate for a full cyclein excess of twice the line power frequency.
 7. In apparatus as setforth in claim 5 wherein the amplitude of each positive component ofenergy is substantially in excess of the amplitude of each of saidnegative components of energy.
 8. In apparatus as set forth in claim 5wherein said positive and negative components of electric energy arepulses.
 9. In apparatus as set forth in claim 5 wherein the peak valueof each said positive component of energy is in the range of 7, 000 to8,600 volts.
 10. In apparatus as set forth in claim 5 wherein the peakvalue of each said negative component of energy is in the range of 3,500 to 4,300 volts.
 11. In apparatus as set forth in claim 5 furtherincluding means for moving the gas between the ionizing point and groundplate at a preselected velocity.
 12. In apparatus as set forth in claim11 further including means for reducing the turbulence of the movinggas.
 13. In apparatus as set forth in claim 5 wherein said generatormeans includes: a converter circuit for changing an input low frequencyline voltage to a DC voltage, an electronic oscillator for changing saidDC voltage to a waveform having repetitive, character-controlledpositive and negative components of electric energy, said waveformhaving a frequency above 120 Hz, and a transformer for stepping up thevoltage of the waveform produced by said electronic oscillator.
 14. Inapparatus as set forth in claim 13 wherein said electronic oscillator isa blocking type oscillator circuit which produces a positive drivenpulse and a negative flyback-type pulse.
 15. In apparatus as set forthin claim 13 further including AC to DC converter means to convertcomponents of electric energy to separate positive and negative DCvoltages.
 16. In apparatus as set forth in claim 13 further includinginput means for applying a low frequency alternating current electricpower to said converter circuit.
 17. In apparatus for producing ions andcontrolling electrostatic potentials, energy dispersing structureincluding a ground plate and an ionizing electrode terminating in anionizing point electrically insulated from the ground plate and spaced apreselected distance from the ground plate, and electric generator meanssecured to the dispersing structure for converting input electric linepower to character-controlled periodic oscillatory pulses of electricenergy having positive and negative components of different amplitudescoupled to said ionizing electrode to produce ions in a body of gasbetween the ionizing point and said ground plate.
 18. In apparatus asset forth in claim 17 wherein said energy dispersing structure includesan upright end casing containing the electric generator means,conductive means extending through the casing, and a support rodreleasably connected at one end to the conductive means supporting aplurality of spaced electrode pins with the ends of the pins definingionizing points, said ground plate being defined by spaced upper andlower conductive plates above and below said support rod, respectively.19. In apparatus as set forth in claim 18 wherein said conductive meansis in the form of a first conductive strip on a printed circuit board towhich said support rod connects and a second conductive strip on saidboard to which said conductive plates connect.
 20. In apparatus as setforth in claim 17 wherein said energy dispersing structure includes anelongated hollow casing, said ground plate being defined by a conductivering mounted in a removable head at the discharge end of the casing andan electrode pin mounted at the center of said conductive ring with asharp point on the end of the pin defining said ionizing point, andfurther including a lattice-like grid assembly across the gas dischargeend of the casing between said ring and pin formed of a plurality offlat intersecting non-conductive strips for dIrecting a gas flow ofrelatively high velocity through the adjoining body of gas in anonturbulent flow.
 21. In apparatus as set forth in claim 17 whereinsaid energy dispersing structure is a generally channel-shaped memberwith conductive portions on the ends thereof forming the ground plates,said ionizing point being defined by an electrode pin mounted in thechannel-shaped member between said end portions, one side wall of saidchannel-shaped member having elongated slots to direct a gas flow alongthe ionizing points.
 22. In apparatus as set forth in claim 17 whereinsaid energy dispersing structure is a barrel terminating in a highvelocity nozzle head with a ring inside the head forming the groundplate, said ionizing point being defined by an electrode pin mounted inthe center of the barrel upstream of the nozzle head, said head havingventuri-like intake sections upstream of the ionizing point.
 23. Inapparatus for producing ions and controlling electrostatic potentials ina duct-like body having a filter and screen across an intake end thereofand having means for circulating the gas through the duct-like body at apreselected velocity, a modular assembly mounted at the intake end ofthe duct-like body adjacent the filter and screen made up of a pluralityof modular units releasably connected and stacked one on another, eachsaid modular unit including an upright end casing having an internalprinted circuit board, a matrix-type pattern of ionizing cells supportedat one end of the casing and arranged in vertically spaced rows and inspaced aligned columns including a first group of generally horizontalsupport rods arranged at vertically spaced intervals and arrangedparallel to one another, each support rod having one end releasablysecured to the end casing at one end, a second group of generallyhorizontal support rods releasably connected end to end to another onein the first group, each said support rod having a plurality ofelectrode pins arranged at equally spaced intervals therealong havingend points located in the same plane defining a plurality of ionizingpoints, an upper ground plate positioned above each support rod and alower grounding plate below each support rod, and a generator mounted inthe end casing having an output terminal connected to said ionizingpoints for converting electric line power to character-controlledperiodic oscillatory pulses of electric ionizing energy having positiveand negative components of different amplitudes, said end casing havingreleasable coupling means for electrically and mechanically connectingto each casing of each successive unit.
 24. In apparatus for producingions and controlling electrostatic potentials in a body of gas, a hollowcasing, an ionizing cell at the discharge end including a conductivering forming a ground plate and an electrode mounted at the center ofsaid ring having a terminal end defining an ionizing point, alattice-like flow control duct assembly across the discharge end of thecasing including a plurality of intersecting non-conductive stripsdefining a plurality of ducts in the one end of the casing for directinggas between the ionizing point and ground plate in a non-turbulent flow,gas-flow generating means operatively associated with the casing fordirecting a relatively high velocity body of gas through the casing fromthe intake to the discharge end thereof, and a generator mounted on thecasing having an output terminal connected to said electrode forapplying character-controlled periodic oscillatory pulses of electricionizing energy having positive and negative components of differentamplitudes to said electrode for producing ions in said body of gas. 25.In apparatus as set forth in claim 24 wherein said casing converges incross section from the intake to the discharge end.
 26. In apparatus forcontrolling electrostatic potentials as set forth in claim 24 whereinsaid gas-flow generating means is an axial fan mounted at the gas intakeend of the casing.
 27. In apparatus as set forth in claim 24 whereinsaid gas-flow generating means is a centrifugal blower mounted on thegas intake end of the casing.
 28. In apparatus as set forth in claim 24wherein said casing is open at each end and adapted to couple into aduct to utilize the gas flow passed through that duct to move the gas.29. In apparatus for producing ions and controlling electrostaticpotentials, the combination comprising: a barrel having a gas inlet andterminating in a nozzle head having an inlet and a restricted outlet, aring-shaped ground plate mounted in the barrel and coaxially alignedtherein, an electrode pin centered in the barrel terminating in anionizing point located in coaxial alignment with the ground plate, meansfor introducing a gas under pressure into the inlet of the barrel toflow between said ground plate and electrode pin, and generator meansmounted on the barrel for producing periodic oscillatory pulses ofelectric ionizing energy having positive and negative components ofdifferent amplitudes for producing ions in a body of gas between saidionizing point and ground plate.
 30. In apparatus as set forth in claim29 further including a handle section containing a valve for controllingthe gas flow into the barrel, said generator means being mounted in ahousing integral with said barrel and releasably attached to said handlesection.
 31. In apparatus for producing ions and controllingelectrostatic potentials, an elongated generally U-shaped support memberhaving a plurality of elongated slots in one side thereof to induce agas flow thereinto, said support member having an induction memberforming an extension of one side thereof, a plurality of ionizing pointsin the support member defined by an elongated support rod extendinglongitudinally of the support member having electrode pins projectingtherefrom at regularly spaced intervals, and a generator mounted on thesupport member having an output terminal connected to said supportelectrode for applying character-controlled periodic oscillatory pulsesof electric ionizing energy having positive and negative components ofdifferent amplitudes to said ionizing points to produce ions.
 32. Inapparatus as set forth in claim 31 further including a cover memberclosing the open side and ends of said support member, said cover memberhaving restricted openings through which said electrode pins extend. 33.In apparatus as set forth in claim 32 further including means to directa gas under pressure into the inside of said support member to bedirected through said restricted openings and past said electrode pins.